Study of the critical and azeotropic behavior of binary mixtures. 2. PVT-x data and azeotropic states of perfluoromethylcyclohexane-isomeric hexane systems
“…Figure 4 shows on a less sensitive scale the other literature results which have comparatively large deviations from our equation (5). Genco et al [27] covered the temperature range from 383 K up to the critical point and their results cut across our work, beginning with deviations of À0.4% at his lower temperature, becoming more positive as the temperature increases and reaching a maximum deviation of 0.8% before diminishing to 0.15 at the critical point. The vapour pressures of de Loos et al [28], reported as part of a wider study of fluid equilibria, show some internal scatter and deviations from equation (5) between about À0.2% and +0.6% but again the deviation is about +0.15% in the critical region.…”
Section: Resultsmentioning
confidence: 58%
“…The coefficients of equation (5) [23] who covered the wide temperature range of (307 to 443) K, report vapour pressures in the band of +0.2% to À0.14% with respect to equation (5), and seven of their results for (393 to 423) K agree within 0.01%. At higher temperatures, (484 to 505) K, the results by Mousa [24] are [22]; , Sauermann et al [23]; À, Mousa [24]; }, Seo et al [25]; s, Bich et al [26]; j, Genco et al [27]; ·, De loos et al [28]; N, Oscarson et al [29]; +, Ida et al [34]; -,…”
Section: Resultsmentioning
confidence: 99%
“…d, This work; r, Willingham et al[22]; , Sauermann et al[23];À, Mousa[24];}, Seo et al[25]; s, Bich et al[26]; j, Genco et al[27]; ·, De loos et al[28]; N, Oscarson et al[29]; thin continuous line, Dykyj et al[30]; thick continuous line, TRC…”
The vapour pressures of n-hexane have been measured using comparative ebulliometry with water as the reference fluid. The measurements cover the temperature and pressure range (315.7 K, 41.1 kPa) to (504.0 K, 2876.8 kPa) and join smoothly with results selected from the literature to provide consistent results down to (289.7 K, 13.8 kPa). The combined data set have been described by a Wagner style equation with a fractional standard deviation of 4.2 AE 10 À5 in the vapour pressure. The critical pressure p c was treated as an adjustable parameter and the value of p c = 3027 kPa was calculated from the smoothing equation using a selected critical temperature of T c = 507.49 K. The calculated normal boiling temperature is T b = 341.866 K and an extrapolation to the triple-point temperature T tp = 177.87 K predicts a triple-point pressure of p tp = 1.23 Pa.
“…Figure 4 shows on a less sensitive scale the other literature results which have comparatively large deviations from our equation (5). Genco et al [27] covered the temperature range from 383 K up to the critical point and their results cut across our work, beginning with deviations of À0.4% at his lower temperature, becoming more positive as the temperature increases and reaching a maximum deviation of 0.8% before diminishing to 0.15 at the critical point. The vapour pressures of de Loos et al [28], reported as part of a wider study of fluid equilibria, show some internal scatter and deviations from equation (5) between about À0.2% and +0.6% but again the deviation is about +0.15% in the critical region.…”
Section: Resultsmentioning
confidence: 58%
“…The coefficients of equation (5) [23] who covered the wide temperature range of (307 to 443) K, report vapour pressures in the band of +0.2% to À0.14% with respect to equation (5), and seven of their results for (393 to 423) K agree within 0.01%. At higher temperatures, (484 to 505) K, the results by Mousa [24] are [22]; , Sauermann et al [23]; À, Mousa [24]; }, Seo et al [25]; s, Bich et al [26]; j, Genco et al [27]; ·, De loos et al [28]; N, Oscarson et al [29]; +, Ida et al [34]; -,…”
Section: Resultsmentioning
confidence: 99%
“…d, This work; r, Willingham et al[22]; , Sauermann et al[23];À, Mousa[24];}, Seo et al[25]; s, Bich et al[26]; j, Genco et al[27]; ·, De loos et al[28]; N, Oscarson et al[29]; thin continuous line, Dykyj et al[30]; thick continuous line, TRC…”
The vapour pressures of n-hexane have been measured using comparative ebulliometry with water as the reference fluid. The measurements cover the temperature and pressure range (315.7 K, 41.1 kPa) to (504.0 K, 2876.8 kPa) and join smoothly with results selected from the literature to provide consistent results down to (289.7 K, 13.8 kPa). The combined data set have been described by a Wagner style equation with a fractional standard deviation of 4.2 AE 10 À5 in the vapour pressure. The critical pressure p c was treated as an adjustable parameter and the value of p c = 3027 kPa was calculated from the smoothing equation using a selected critical temperature of T c = 507.49 K. The calculated normal boiling temperature is T b = 341.866 K and an extrapolation to the triple-point temperature T tp = 177.87 K predicts a triple-point pressure of p tp = 1.23 Pa.
“…These deviations are smaller than those for the original SAFT EOS (up to 12−18%) but still bigger than those for the crossover cubic model (about 1−2%). 5 6 7 VLE data for n -hexane ,− (symbols) with predictions of the crossover SAFT equation of state (solid lines) and classical SAFT EOS 10 (short-dashed lines). 8 VLE data for n -decane ,− (symbols) with predictions of the crossover SAFT equation of state (solid lines) and classical SAFT EOS …”
Section: Comparison With Experimental Datamentioning
confidence: 99%
“…VLE data for n -hexane ,− (symbols) with predictions of the crossover SAFT equation of state (solid lines) and classical SAFT EOS 10 (short-dashed lines).…”
Section: Comparison With Experimental Datamentioning
In this paper we develop a crossover modification of the statistical associating fluid theory (SAFT)
equation of state for macromolecular chain fluids which incorporates the scaling laws asymptotically close to the critical point and is transformed into the original classical SAFT equation of
state far away from the critical point. A comparison is made with experimental data for pure
methane, ethane, n-hexane, n-decane, and n-eicosane in the one- and two-phase regions. We
also present comparisons with experimental single-phase data for n-triacontane and n-tetracontane. We show that, over a wide range of states, the crossover SAFT model yields a
much better representation of the thermodynamic properties of pure fluids than the original
SAFT equation of state. The crossover SAFT equation of state reproduces the saturated pressure
data in the entire temperature range from the triple point to the critical temperature with an
average absolute deviation (AAD) of about 3.8%, the saturated liquid densities with an AAD of
about 1.5%, and the saturated vapor densities with an AAD of about 3.4%. In the one-phase
region, the crossover SAFT equation represents the experimental values of pressure in the critical
region with an AAD of about 2.9% in the region bounded by 0.05ρc ≤ ρ ≤ 2.5ρc and T
c ≤ T ≤ 2T
c,
and the liquid density data with an AAD of about 3% at the pressures up to P = 2000 bar. For
the n-alkanes C
m
H2
m
+2 with the molecular weight M
w > 142 (m > 10), the crossover SAFT model
contains no adjustable parameters and can be used for the pure prediction of the fluid
thermodynamic surface.
dation Grant ENG 77-15953 is gratefully acknowledged. We thank the Calgon Corp. for providing activated carbon. after initial heat treatment reacted/(kg of virgin carbon unburned) (s) generation, m2 The volumetric and phase behavior of propane-perfluorocyclobutane mixtures has been determined in the critical region. This system exhibits a minimum temperature point in its critical locus curve and forms a positive critical azeotrope. The measured critical points in this system and their correlation using an extended corresponding states principle are reported in this paper.
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